Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2019 Publisher: Aventis Pharma Ltd, 410 Thames Valley Park Drive, Reading, Berkshire, RG6 1PT, UK Trading as: Sanofi, 410 Thames Valley Park Drive, Reading, Berkshire, RG6 1PT, UK
Largactil injection is a phenothiazine neuroleptic. It is indicated in the following conditions:
Deep intramuscular injection.
Oral route administration should be used wherever possible.
Parenteral formulations may be used in emergencies. They may only be administered by deep intramuscular injection. Largactil is too irritant to give subcutaneously. Repeated injections should be avoided if possible.
Adults: A single deep intramuscular injection of 25-50mg followed by oral therapy will suffice in many cases, but the intramuscular dose may be repeated if required at 6 to 8 hour intervals. As soon as possible oral administration should be substituted.
Elderly: Should be started on half or even quarter of the adult dosage.
Dosage of chlorpromazine in schizophrenia, other psychoses, anxiety and agitation, childhood schizophrenias and autism:
| Route | Adults | Children under 1 year | Children 1-5 years | Children 6-12 years | Elderly or debilitated patients |
|---|---|---|---|---|---|
| i.m. | For acute relief of symptoms 25-50 mg every 6-8 hours. | Do not use unless need is life saving. | 0.5 mg/kg bodyweight every 6-8 hours. Dosage is not advised to exceed 40 mg daily. | 0.5 mg/kg bodyweight every 6-8 hours. Dosage is not advised to exceed 75 mg daily. | Doses in the lower range for adults should be sufficient to control symptoms i.e. 25 mg 8 hourly. |
Hiccup:
| Indication | Route | Adults | Children under 1 year | Children 1-5 years | Children 6-12 years | Elderly or debilitated patients |
|---|---|---|---|---|---|---|
| Hiccups | i.m. | 25-50 mg and if this fails 25-50 mg in 500-1000 ml sodium chloride injection by slow intravenous infusion. | No information available. | |||
Nausea and vomiting of terminal illness:
| Route | Adults | Children under 1 year | Children 1-5 years | Children 6-12 years | Elderly or debilitated patients |
|---|---|---|---|---|---|
| i.m. | 25 mg initially then 25-50 mg every 3-4 hours until vomiting stops then drug to be taken orally. | Do not use unless need is life saving. | 0.5 mg/kg 6-8 hourly. It is advised that maximum daily dosage should not exceed 40 mg. | 0.5 mg/kg every 6-8 hours. It is advised that maximum daily dosage should not exceed 75 mg. | Not recommended. |
Toxicity and treatment of overdosage: Symptoms of chlorpromazine overdosage include drowsiness or loss of consciousness, hypotension, tachycardia, ECG changes, ventricular arrhythmia’s, hypothermia, Parkinsonism, convulsions and coma. Severe extra-pyramidal dyskinesias may occur.
Treatment should be symptomatic with continuous respiratory and cardiac monitoring (risk of prolonged QT interval) until the patients conditions resolves.
If the patient is seen sufficiently soon (up to 6 hours) after ingestion of a toxic dose, gastric lavage may be attempted. Pharmacological induction of emesis is unlikely to be of any use. Activated charcoal should be given. There is no specific antidote. Treatment is supportive.
Generalised vasodilation may result in circulatory collapse; raising the patient’s legs may suffice. In severe cases, volume expansion by intravenous fluids may be needed; infusion fluids should be warmed before administration in order not to aggravate hypothermia.
Positive inotropic agents such as dopamine may be tried if fluid replacement is insufficient to correct the circulatory collapse. Peripheral vasoconstriction agents are not generally recommended; avoid the use of adrenaline.
Ventricular or supraventricular tachy-arrhythmias usually respond to restoration of normal body temperature and correction of circulatory or metabolic disturbances. If persistent or life threatening, appropriate anti-arrhythmic therapy may be considered. Avoid lidocaine and, as far as possible, long acting anti-arrhythmic drugs.
Pronounced central nervous system depression requires airway maintenance or, in extreme circumstances, assisted respiration. Severe dystonic reactions usually respond to procyclidine (5-10mg) or orphenadrine (20-40mg) administered intramuscularly or intravenously. Convulsions should be treated with intravenous diazepam.
Neuroleptic malignant syndrome should be treated with cooling. Dantrolene sodium may be tried.
The shelf life of the Largactil Injection is 36 months.
Keep ampoules in outer carton in order to protect from light. Discoloured solution should not be used.
Largactil Injection 2.5% w/v is supplied in boxes containing 10 × 1 ml or 10 × 2 ml in glass ampoules.
None.
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